'trace(Z) is valid only if the elements along the diagonal have the same curvature'


(xucheng) #1

What’s the meaning of ‘trace(Z) is valid only if the elements along the diagonal have the same curvature’ in The CVX Users’ Guide?


(Michael C. Grant) #2

It means that you can’t take the trace of a matrix whose diagonal has a mixture of convex and concave elements. It’s basically a straightforward application of the fact that trace(Z) = sum(diag(Z)).


(xucheng) #3

Ok! Get it,Thanks:smile: